Problem: Installed a new Honeywell RTH9580 Wi-Fi thermostat for my house. Connected the wires to the appropriate connectors and mounted the unit. All seem to be working well except when the thermostat would try to initiate the heating process, it would only blow cold air. I would have to reset the thermostat a few times before the burners would initiate. Another thing that would happen was that the fan would turn on 30 min before the schedule would call for the heat to turn on. It was kind of annoying and would wake me up at night with the fan constantly turning on.
Solution: For the premature fan issue, it turns out that this is a feature of the thermostat was their “Smart Response Technology” which would learn how your home heats and if you had it set to 70 for 6am, it might start heating the home at 5am in order for it to reach temperature by six. I didn’t like that because I just wanted the heat to turn on at the time I specified. So I went into the menu – preferences and turned off the “Smart Response Technology” feature.
For the cold air issue, it turns out that I mis-read the settings and the thermostat was setup for an electric heating system. So I re-ran the setup and made sure it was set to gas and the thermostat and furnace has been working like a champ.
*Love that I can change temp just by using the app on my iPhone!
Update: I kept on having the problem and after some digging I realized my flame sensor needed cleaning. Once I cleaned it, we were back in business.